Crystallization behavior of a thermoplastic polyimide derived from 3,3′,4,4′‐oxydiphthalic dianhydride and 4,4′‐oxydianiline

Abstract

AbstractNonisothermal and isothermal crystallization kinetics of an aromatic thermoplastic polyimide derived from 3,3′,4,4′‐oxydiphthalic dianhydride and 4,4′‐oxydianiline have been investigated by means of differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction. The results for nonisothermal crystallization study showed that a weak melting peak appeared during the first heating process, whereas no crystallization peak appeared in the DSC curve during the subsequent cooling process. On the other hand, the study for the isothermal crystallization in the temperature range of 260–330°C showed that a new exothermic peak appeared at lower temperature for the samples crystallized for 100 min at 300°C. Moreover, the results indicated that the crystallization behaviors were largely affected by the crystallization temperature and crystallization time. During the annealing process, the melting enthalpy tended to increase with increasing annealing temperature and annealing time. More interesting was that two melting endotherms appeared when the annealing temperature was lower than 300°C. However, when the annealing temperature was higher than 330°C, only one melting endotherm appeared. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008